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Friday, 29 February 2008

A couple of these came to light. One outside the house, the other inside.

Pale Brindled Beauty - Phigalia pilosaria.

Both were males: the females are wingless.

This broad-leaf species is regarded as scarce in NW Ireland, but is probably just under-recorded.

Not quite the beauty that its name would suggest....I rather think the people who gave the names out were having a bit of a giggle to themselves.

This is a species that has two forms: one dark, the other pale. The dark version flourished in polluted places like central London, where it still outnumbers the pale version by 60:40. Ours are pale, of course.

I saw the old flower-heads, and I pulled them off so I'm cheating on this one: Largest leaves 2-3 cm. long.For this one I will take family. The main reason is I don't know which one it is and I won't know until about June. Specimen about 5 cm. across:

I'll have to accept one of two on this one, although I have my favourite for which:

Here's the little (2mm) weevil from yesterday:

Not the best shot on the planet, but at least it proves that it's a weevil. The grainy appearance is due to me shooting at ISO 1600 and zooming right in. When the light gets better I'll go back to ISO 400.

Tuesday, 26 February 2008

I thought you might be interested in an update on a series of observations that I have been making over the last couple of years: I have been observing an ichneumonid (parasitic wasp) ovipositing in Nematus pavidus (sawfly) larvae on Willow.

Today I got (from Gavin Broad at the NHM, London) further fascinating information:

It turns out she's a Mesochorus sp. These are hyperparasites and only lay their eggs in larvae which have already been parasitised by other ichneumonids (or, indeed Tachinids - parasitic flies). Rather than being parasitic on the Sawfly larvae, Mesochorus larvae are parasitic on the primary parasite's larvae. So the photographs I have taken completely miss out an intermediate stage: the initial parasitisation. Given the time taken from the sawfly eggs hatching to my photographs being taken, the initial parasitisation must be very quick indeed. This is simply enthralling.

It might also explain the behaviour that I noticed being used when the hyperparasite was checking out the larvae. She banged her front feet down beside the head of the larva and appeared to be watching for the sawfly larva's normal defensive posture change. I previously thought she was checking to see if others like her had already paid a visit, in which case she would move on to another larva. It turns out she was checking to ensure that the larva had indeed been pre-parasitised, so that she could parasitise the primary parasite. Wonderful.

I'm very interested in species dependencies, and this one is four deep: Willow, Sawfly larva, primary parasite, hyperparasite.

As it happens, I saw my first ichneumonid of 2008 on Sunday, although I didn't realise it until I blew up the pictures on the PC. Here's the shot:

The photo contains 4 insects. The ichneumonid (top left), a wonderful crimson weevil (bottom right) and a copulating pair of Chrysomelid beetles (centre right). I can't go in any closer: each of the insects is less than 2mm long. The moving red dot of the weevil was all I could see with the naked eye. Now all I have to do is identify the weevil and the chrysomelids. It starts.

Tuesday, 19 February 2008

Last week we had four beautiful days of sunshine: almost as many as we could expect in a whole Donegal summer. This week we've had four consecutive nights of frost, including the coldest night of the winter so far (-5 Celsius). Imagine my surprise when I looked outside my window today and saw:I usually expect to see Willow catkins around the first week of March. In that case I need to get out and look for Blackthorn and other Prunus flowers: they are usually out at the same time as the first catkins. This is proving to be a very early year (Daffodils are out in a few locations, too.)

Monday, 18 February 2008

I was walking along the track through the high boggy area (clue!) when I noticed that an earth wall - created to deter joy-riders - had become covered in little rosettes of young plants. I always like to test my identification skills on vegetative states, so I began to mentally catalogue the species I found.

I thought you might like to do the same.

First, an easy one. Leaves about 12mm long:

Another easy one. Leaves about 6mm long:

I think this is less easy, but there is a strong clue in the picture. Leaves about 10mm long.

This one is definitely more difficult. The leaves are about 5mm long, and show a feature that will (according to some references) readily identify the species, although this feature is difficult to find later in the season, when you would like it to be there to resolve disputes.

This could be a stumbling block unless you think laterally. Leaves about 12-15 mm long:

I'm always surprised that our earliest frogspawn is always at the highest locations. Mongorrey is the highest local point for miles around, and this young pond is in the most exposed area possible. Yet year after year I know that I can find spawn here days before I find it in lower, more sheltered areas.While I was down photographing the spawn I noticed this Water Boatman swimming near the bottom of the pond. Corixa punctata.This pond is quite interesting. When the Spruce plantation was clear-felled (yay!) about 5 years ago, a large area was excavated to use for log storage. This pond formed as a by-product. For the first couple of years it lay stagnant, but now various water plants (Pond Weed, Ivy-leaved Water Crowfoot, Callitriche) have established and water beetles and bugs have arrived. I'll continue to monitor the arrival of new species as the pond matures.

Friday, 15 February 2008

The other day I showed ditch liverworts. This is a very common liverwort on trees: Frullania dilatata. I find this everywhere, even in the wildlife deserts to be found inside Spruce plantations. Individual leaves on this species are sub-millimetre in size. Patch about 6 cm. across.There are, of course plenty of lichens in the shot, including Pertusaria sp. (pale green, top centre and top right) and a Graphis sp. (bottom centre).

As I was looking at the Hazel catkins, I noticed that the river was very much smoother than usual. The Finn can be quite ferocious at times.Notice the astonishing depth of field (100m?) for a macro lens! I only managed that because I'm experimenting with ISO 1600, which is as fast as the camera goes. Not too noisy, I think. The image stats say 160th at f22.

And this astonishing shot is very rare to find locally. This is the con-trail of a jet reflected in the water surface.I don't expect to find a blue sky, never mind a glass-like river surface.

As Gill observed yesterday, the edges of the mine made by the mining fly Phytomyza ilicis on Holly leaves are currently very sharp:I spent a couple of years fretting over the problem that only one single species of insect mines Holly leaves. Holly must be a wonderful place to have a mine: hard leaves and sharp points are great protection. The answer to the dilemma is stranger than the solutions that readily come to mind. All leaves attempt to heal themselves, and Holly is no exception. Holly has a very hard exterior surface, and when it heals itself, it does so with great strength. That means that any insect close to the healing point would be liable to be squashed by the leaf surfaces. Phytomyza ilicis is the only miner that can move faster than the leaf heals, so that's why it's the only miner in Holly. At this time of year the sunlight is weak and the healing process is slow, so the edges of the mine are sharper than they are in summer.

Eagle-eyed observers will notice that this unfortunate individual hasn't made it. Even thick Holly leaves don't make you completely immune to the attentions of parasitic wasps.

And this is typical damage caused by the Vine Weevil - Otiorhynchus sulcatus .Otiorhynchus sulcatus also feeds on Rhododendron and I expect you'll find similar damage on vine leaves, although I don't get to see too many of those in Donegal....

Wednesday, 13 February 2008

I was making a quick visit to Drumboe Wood in Ballybofey today and I took some pictures of various parasites on Holly (Leaf-miners, weevils, that sort of thing). Suddenly I noticed this fungal rust on a few of the leaves and thought "Hmmm...never seen a rust on Holly before".

It looks very much like Puccinia-type rusts, but when I got back to the reference books I found:

there are no documented fungi that grow on healthy Holly leaves

there are no documented Puccinias that grow on Holly at all.

After consultation and internet research, it turns out that a new Holly Puccinia was discovered in Europe in 1977, so I need to track down its specification and see if it matches what I have.

Another possibility was the Phycopeltis algal infection that can grow on Holly leaves, but that's only on the surface: this clearly goes into the leaf, as evidenced by the dark ring around the infection.

It's an Irish first, whatever it is.

This is the kind of thing that keeps me going: amateurs can still discover new things in new places....wonderful.

Tuesday, 12 February 2008

Liverworts are fascinating little plants that can be found on the back wall of ditches, on damp walls and hidden in rock crevices, woodland paths and tree-trunks : anywhere that it's fairly dark and damp.

Thallose liverworts are easy to identify: they are ribbon-like with a flat main structure (thallus). This is Conocephalum conicum, showing the lizard-skin-like thallus which readily identifies it.(Width of thallus about 10mm):And here's a habit shot, specimen about 10cm. long:

Leafy liverworts are more difficult to separate from mosses without magnification. This wonderful specimen is Plagiochila porelloides, with the main 'stem' in the foreground being about 12mm long. You really do need to get a magnifying glass on these to identify them as liverworts, and you need higher magnification to identify them to species. The leaves are often very complex, with folds and pockets, presumably to retain water if their source dries out.

Having said all that, what about this one?

Well, just to complicate things, this is a moss: Hookeria lucens. The leaf cells are so large you can see them with the naked eye. Specimen shown about 15mm long.

So what differentiates a liverwort from a moss? The defining difference is in the rhizoids (root-like structures used to grip the substrate). In mosses these are multi-cellular, but in liverworts they are single-celled structures. That's all very well under the microscope, but in the field we have to use a combination of features, such as leaf arrangement, leaf lobing (no mosses have leaf lobes), presence of thallus and shape of reproductive organs, if visible.

Sunday, 3 February 2008

I woke up this morning to a light covering of snow. It's always interesting to have a look for tracks in snow because you can see what has been up and about before you.

These bird tracks immediately caught my eye:

But I had something of a problem. The footprints were about the same size as a Thrush or Blackbird would make...say 4 cm. long. But the bird is a walker, not a hopper. So it's not thrush family. The stride pattern is quite long, so it's a bird with feet that are small for the size of the bird.

Keeping in mind that I live in a more or less rural location, what bird do you think made this trail?

(I have a pretty strong candidate, since I know what birds we have around here, but I thought I'd throw the question open.)